1、.Diffuse type：T2WI shows multiple low signal nodules in joint and popliteal space,high signal also can be seen in partial nodules with joint effusion shows hyperintense.Articular surface of tibial platform was invaded and show mixed signal surrounding by low signal ring.Low signal nodule also can be
2、 seen in the suprapatellar bursa.弥漫型PVNS:T2WI 示关节腔内及腘窝多发低信号结节,部分结节内见高信号区,关节腔积液呈高信号。胫骨关节面破坏,呈混杂信号,周围伴低信号环。髌上囊亦见低信号结节.Focal type：T1WI shows well-distributed low signal mass in infrapatellar bursa with a little effusion and joint structures is normal.局灶型PVNS,T1WI 示髌下囊内肿块,肿块呈均匀低信号,伴关节腔少量积液,关节骨结构正常.Diffu
3、se type of knee joint:T1WI shows low signal irregular thickened synovium on the anterior and the posterior cruciate ligament.膝关节弥漫型PVNS。MR T1WI 示前、后交叉韧带表面有不规则增厚的滑膜覆盖,增厚的滑膜呈低信号.T2WI also shows low signal irregular thickened synovium on the anterior and the posterior cruciate ligament.Low signal nodul
4、es can be seen in the effusion of suprapatellar bursa.T2WI shows mixed signal of multiple bone destruction,surrounding by a rim of hypointensity.T2WI 示前、后交叉韧带表面有不规则增厚的低信号滑膜覆盖,髌上囊积液内见低信号结节(图5)。T2WI 示股骨、胫骨多发骨破坏,破坏区高低信号混杂,伴周边低信号环(图6).Figure 4:T1WI shows diffusive thickened synovium.Suprapatellar bursa
5、become large because of cloddy synovium.Infrapatellar fat pad disappear instead of proliferous synovium,anterior horn of the lateral meniscus was involved.Figure 5:T2WI:diffusive proliferous synovium shows low signal because of hemosiderin deposition.MRI T1 加权像,滑膜弥漫性增厚,髌上囊因被团状的滑膜组织占据而扩大,髌下脂肪垫内脂肪缺失,代
6、之以增厚的滑膜组织,外侧前角半月板受累及。图5 MRI 示T2 加权像,弥漫增厚的滑膜呈低信号,系含铁血黄素沉积所致。.MRI shows nodule on the surface of anterior cruciate ligament and bubble low signal under articular surface of tibial platform.Histopathologic section shows proliferous synovial cell,interstitial(within tissues)show roundness and polygon.Pa
7、rtial cells have hemosiderin deposition,multinucleated giant cells can be seen locally.MRI 示矢状面T1、T2 加权像,前十字韧带表面结节影,胫骨关节面下类圆形低信号骨质缺损。HE400滑膜细胞明显增生,间质浸润的组织呈圆形或多角形,部分细胞吞噬含铁血黄素,局部见融合的多核巨细胞。.Figure 1.T1WI:stratified singular signal in the popliteal fossa shows slightly high centre and iso-low rim.Irregu
8、lar banded low signal can be seen in the suprapatellar bursa and infrapatellar fat pad.Obviously low signal can be seen below the articular surface of tibia.图图1 右膝关节矢位T1W I示腘窝内见异常信号,呈中心稍高,周边等、低信号的分层状排列,髌上囊及髌下脂肪囊内见形态不规则的片带状低信号影,胫骨前上缘关节面下见小囊状明显低信号影。Figure 2.fat-suppressed T2WI:stratified singular sign
9、al in the popliteal fossa shows obviously high centre and iso-low rim.Irregular banded high signal can be seen in the suprapatellar bursa and infrapatellar fat pad.Mixed signal can be seen below the articular surface of tibia.图图2右膝关节矢位压脂T2W I示腘窝内异常信号,呈中心明显高、周边等、低信号的分层状排列,髌上囊及髌下脂肪囊内见形态不规则的片带状高信号影,胫骨前
10、上缘关节面下见小囊状高、低混杂信号影。.FIG 1.Lateral radiograph of the cervical spine shows a soft tissue mass destroying the posterior elements of the lower cervical spine(arrow).There are no foci of calcifications seen within this mass.图1：颈椎侧位片示软组织肿块破坏颈椎后下部结构，肿块内无钙化点。.FIG 2.Sagittal T1-weighted images before (A)and
11、after(B)contrast dministrationshow an expansile mass lesion involving the posterior elements of C5 and C6 vertebra.This mass shows homogeneous enhancement after contrast material administration.It is seen to displace the thecal sac anteriorly.图2.矢状位T1WI增强前后示膨胀性的肿块侵犯惊5、6椎体及其附件，肿块呈均匀强化，向前推压硬膜囊。.Axial
12、T1-weighted postcontrast image with fat suppression shows the exact delineation of the mass with an anteriorly displaced thecal sac(arrow).轴位增强压脂T1WI示界限明确的肿块向前推压硬膜囊。Histopathologic section of pigmented villonodular synovitis depicting sheetlike growth within the main tumor mass,which is comprised of mononuclear cells and multinucleated giant cells within the collagenized stroma.Hematoxylin and eosin.组织病理学示变形增殖的滑膜细胞，间以散在的的单核细胞和多核巨细胞。（HE染色）.
